Anal Bleeding: An Overview
Anal bleeding is a symptom of a disease rather than a disease itself. It can occur as the result of a number of different conditions, some of which are life threatening.
The most common cause of anal bleeding is
hemorrhoids. However, more serious causes can also occur. So while the cause of anal bleeding may or may not turn out to be serious, it is still important to locate the source of the bleeding.
It is very important to see your doctor if you have anal bleeding and:
- You are older than 50
- Have a family history of colon or rectal cancer
- The bleeding occurs between bowel movements
- The blood is dark red or maroon
- You have tar-like, black stools.
Anal Bleeding: The Anatomy
The digestive or gastrointestinal (GI) tract includes the:
- Esophagus
- Stomach
- Small intestine
- Large intestine (colon)
- Rectum
- Anus.
Anal bleeding can come from one or more of these areas. For example, bleeding may come from a small area such as an ulcer on the lining of the stomach (known as a stomach ulcer or peptic ulcer), or from a large surface such as an inflamed section of the colon.
Anal bleeding can sometimes occur without the person noticing it. This type of bleeding is called occult or hidden bleeding. Fortunately, simple tests can detect occult blood in the stool.
Common causes of anal bleeding can include:
In the lower digestive tract, the large intestine and rectum are frequent sites of bleeding. Hemorrhoids are the most common cause of visible blood in the digestive tract, especially blood that appears bright red. Hemorrhoids are enlarged veins in the anal area that can rupture and produce bright red blood, which can show up in the toilet or on the toilet paper. If red blood is seen, however, it is essential to exclude other causes of anal bleeding since the anal area may also be the site of cuts (fissures), inflammation, or cancer.
Benign growths (which are non-cancerous) or polyps of the
colon are very common and are thought to be forerunners of cancer. These growths can cause either bright red blood or occult bleeding.
Colorectal cancer is the third most common of all cancers in the United States and often causes occult bleeding at some point, but not necessarily visible bleeding.
Inflammation from various causes can produce extensive bleeding from the colon. Different intestinal infections can cause inflammation and bloody
diarrhea. Ulcerative colitis can produce inflammation and extensive surface bleeding from tiny ulcerations. Crohn's disease of the large intestine can also produce bleeding.
Diverticular disease caused by diverticula (pouches in the colon wall) can result in massive bleeding.
Finally, as a person gets older, abnormalities may develop in the blood vessels of the large intestine (angiodysplasia). This may result in recurrent bleeding.
Patients taking blood-thinning medications (warfarin) may have gastrointestinal bleeding, especially if they take drugs like aspirin.
Symptoms of Anal Bleeding
The symptoms of anal bleeding depend upon the site and severity of the bleeding. Some common symptoms include:
- Bright red blood coating the stool
- Dark blood mixed with the stool
- Black or tarry stool.
There are also symptoms of anal bleeding that might indicate whether the bleeding is acute or chronic. Symptoms of acute anal bleeding include:
- Any of the bleeding symptoms above
- Weakness
- Shortness of breath
- Dizziness
- Crampy abdominal pain
- Feeling faint
- Diarrhea.
Symptoms of chronic anal bleeding include:
- Any of bleeding symptoms above
- Weakness
- Fatigue
- Shortness of breath
- Lethargy
- Feeling faint.
If blood is coming from the rectum or the lower
colon, bright red blood will coat or mix with the stool. The stool may be mixed with darker blood if the bleeding is higher up in the colon or at the far end of the small intestine. When there is bleeding in the esophagus, stomach, or duodenum, the stool is usually black or tarry.
If the bleeding is occult, the patient might not notice any changes in stool color.
If sudden massive bleeding occurs, a person may feel weak, dizzy, faint, short of breath, or have crampy abdominal pain or diarrhea. Shock may occur, with a rapid pulse, drop in
blood pressure, and difficulty in producing urine. The person may become very pale.
If bleeding is slow and occurs over a long period of time, a gradual onset of fatigue, lethargy, shortness of breath, and pallor (a pale appearance) from the anemia will result. The term "anemia" means there is a deficiency of the blood's iron-rich substance, hemoglobin.
It's important to locate the site of the bleeding. A complete history and physical examination are an essential part of making a diagnosis. Symptoms such as changes in bowel habits, stool color (to black or red) and consistency, and the presence of pain or tenderness may tell the doctor which area of the GI tract is affected.
Since eating iron-rich foods, bismuth (Pepto Bismol®), or foods such as beets can give the stool the same appearance as bleeding from the digestive tract, a doctor must test the stool for blood before offering a diagnosis. A blood count will indicate whether the patient is anemic and also will give an idea of the extent of the bleeding and how chronic it may be.
Endoscopy
Endoscopy is a common diagnostic technique that allows direct viewing of the site of bleeding. Because the endoscope can detect lesions and confirm the presence or absence of bleeding, doctors often choose this method to diagnose patients with acute bleeding. In many cases, the doctor can use the endoscope to treat the cause of anal bleeding as well.
The endoscope is a flexible instrument that can be inserted through the mouth or rectum. The instrument allows the doctor to see into the esophagus, stomach, duodenum (esophago-duodenoscopy),
colon (
colonoscopy), and rectum (
sigmoidoscopy). The endoscope also allows the doctor to collect small samples of tissue (biopsies), to take photographs, and to stop the bleeding.
Small bowel endoscopy, or enteroscopy, is a procedure that uses a long endoscope. This endoscope may be used to pinpoint unidentified sources of bleeding in the small intestine.
A new diagnostic instrument called a capsule endoscope is swallowed by the patient. The capsule contains a tiny camera that transmits images to a video monitor. It is used most often to find bleeding in portions of the small intestine that are hard to reach with a conventional endoscope.
Other Procedures
Several other methods are available to locate the source of gastrointestinal bleeding. These can include:
- Barium x-rays
- A CT scan
- Angiography
- Radionuclide scanning.
Barium x-rays are generally less accurate than endoscopy in locating bleeding sites. Some drawbacks of barium x-rays include:
- They may interfere with other diagnostic techniques if used for detecting acute bleeding
- They expose the patient to x-rays
- They do not offer the capabilities of biopsy or treatment.
Another type of x-ray, called a CT scan, is particularly useful for inflammatory conditions and cancer.
Angiography is a technique that uses dye to highlight blood vessels. This procedure is most useful in situations when the patient is acutely bleeding. When this happens, the dye leaks out of the blood vessel and identifies the site of bleeding. In some situations, angiography allows medicine to be injected into the arteries that may stop the gastrointestinal bleeding.
Radionuclide scanning is a noninvasive screening technique used for locating sites of acute bleeding, especially in the lower GI tract. This technique involves injection of small amounts of radioactive material. Then, a special camera produces pictures of organs, allowing the doctor to detect the site of a GI bleed.
Endoscopy is the primary diagnostic and therapeutic procedure for most causes of gastrointestinal bleeding. Active bleeding from the upper GI tract can often be controlled by injecting chemicals directly into a bleeding site with a needle that is passed through the endoscope. A physician can also cauterize (treat with heat) a bleeding site and the surrounding tissue with a heater probe or electrocoagulation device. These devices are also passed through the endoscope. Laser therapy is useful in certain specialized situations.
Once anal bleeding is controlled, medicines are often prescribed to prevent the bleeding from coming back. Medicines are useful for things like H. pylori infections, esophagitis, ulcers, other infections, and innflammatory bowel disease (IBD). Medical treatment of ulcers -- including the elimination of H. pylori -- to ensure healing and maintenance therapy to prevent the return of ulcers can also lessen the chance of recurrent bleeding.
Removing polyps with an endoscope can control the bleeding from
colon polyps. Removing
hemorrhoids by banding or various heat or electrical devices is effective in patients who suffer hemorrhoidal bleeding on a recurrent basis. Endoscopic injection or cauterization can be used to treat sites of gastrointestinal bleeding throughout the lower intestinal tract.
Endoscopic techniques do not always control bleeding. Sometimes, angiography may be used. However, surgery is often needed to control active, severe, or recurrent bleeding when endoscopy is not successful.
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